Grid system

Bootstrap includes a powerful mobile-first flexbox grid system for building layouts of all shapes and sizes. It’s based on a 12 column layout and has multiple tiers, one for each media query range. You can use it with Sass mixins or our predefined classes.

How it works

Bootstrap’s grid system uses a series of containers, rows, and columns to layout and align content. It’s built with flexbox and is fully responsive. Below is an example and an in-depth look at how the grid comes together.

One of three columns

One of three columns

One of three columns

The above example creates three equal-width columns on small, medium, large, and extra large devices using our predefined grid classes. Those columns are centered in the page with the parent .container.

Breaking it down, here’s how it works:

Containers provide a means to center your site’s contents. Use .container for fixed width or .container-fluid for full width.

Rows are horizontal groups of columns that ensure your columns are lined up properly. We use the negative margin method on .row to ensure all your content is aligned properly down the left side.

Content should be placed within columns, and only columns may be immediate children of rows.

Thanks to flexbox, grid columns without a set width will automatically layout with equal widths. For example, four instances of .col-sm will each automatically be 25% wide for small breakpoints.

Column classes indicate the number of columns you’d like to use out of the possible 12 per row. So, if you want three equal-width columns, you can use .col-sm-4.

Column widths are set in percentages, so they’re always fluid and sized relative to their parent element.

Columns have horizontal padding to create the gutters between individual columns, however, you can remove the margin from rows and padding from columns with .no-gutters on the .row.

There are five grid tiers, one for each responsive breakpoint: all breakpoints (extra small), small, medium, large, and extra large.

Grid tiers are based on minimum widths, meaning they apply to that one tier and all those above it (e.g., .col-sm-4 applies to small, medium, large, and extra large devices).

You can use predefined grid classes or Sass mixins for more semantic markup.

Grid options

While Bootstrap uses ems or rems for defining most sizes, pxs are used for grid breakpoints and container widths. This is because the viewport width is in pixels and does not change with the font size.

See how aspects of the Bootstrap grid system work across multiple devices with a handy table.

Extra small<576px

Small≥576px

Medium≥768px

Large≥992px

Extra large≥1200px

Grid behavior

Horizontal at all times

Collapsed to start, horizontal above breakpoints

Max container width

None (auto)

540px

720px

960px

1140px

Class prefix

.col-

.col-sm-

.col-md-

.col-lg-

.col-xl-

# of columns

12

Gutter width

30px (15px on each side of a column)

Nestable

Yes

Offsets

Yes

Column ordering

Yes

Auto-layout columns

Utilize breakpoint-specific column classes for equal-width columns. Add any number of unit-less classes for each breakpoint you need and every column will be the same width.

Equal-width

For example, here are two grid layouts that apply to every device and viewport, from xs to xl.

Setting one column width

Auto-layout for flexbox grid columns also means you can set the width of one column and the others will automatically resize around it. You may use predefined grid classes (as shown below), grid mixins, or inline widths. Note that the other columns will resize no matter the width of the center column.

Variable width content

Using the col-{breakpoint}-auto classes, columns can size itself based on the natural width of its content. This is super handy with single line content like inputs, numbers, etc. This, in conjunction with horizontal alignment classes, is very useful for centering layouts with uneven column sizes as viewport width changes.

Equal-width multi-row

Create equal-width columns that span multiple rows by inserting a .w-100 where you want the columns to break to a new line. Make the breaks responsive by mixing the .w-100 with some responsive display utilities.

Responsive classes

Bootstrap’s grid includes five tiers of predefined classes for building complex responsive layouts. Customize the size of your columns on extra small, small, medium, large, or extra large devices however you see fit.

All breakpoints

For grids that are the same from the smallest of devices to the largest, use the .col and .col-* classes. Specify a numbered class when you need a particularly sized column; otherwise, feel free to stick to .col.

Mix and match

Don’t want your columns to simply stack in some grid tiers? Use a combination of different classes for each tier as needed. See the example below for a better idea of how it all works.

.col .col-md-8

.col-6 .col-md-4

.col-6 .col-md-4

.col-6 .col-md-4

.col-6 .col-md-4

.col-6

.col-6

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<!-- Stack the columns on mobile by making one full-width and the other half-width --><divclass="row"><divclass="col col-md-8">.col .col-md-8</div><divclass="col-6 col-md-4">.col-6 .col-md-4</div></div><!-- Columns start at 50% wide on mobile and bump up to 33.3% wide on desktop --><divclass="row"><divclass="col-6 col-md-4">.col-6 .col-md-4</div><divclass="col-6 col-md-4">.col-6 .col-md-4</div><divclass="col-6 col-md-4">.col-6 .col-md-4</div></div><!-- Columns are always 50% wide, on mobile and desktop --><divclass="row"><divclass="col-6">.col-6</div><divclass="col-6">.col-6</div></div>

Alignment

Use flexbox alignment utilities to vertically and horizontally align columns.

Vertical alignment

One of three columns

One of three columns

One of three columns

One of three columns

One of three columns

One of three columns

One of three columns

One of three columns

One of three columns

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<divclass="container"><divclass="row align-items-start"><divclass="col">
One of three columns
</div><divclass="col">
One of three columns
</div><divclass="col">
One of three columns
</div></div><divclass="row align-items-center"><divclass="col">
One of three columns
</div><divclass="col">
One of three columns
</div><divclass="col">
One of three columns
</div></div><divclass="row align-items-end"><divclass="col">
One of three columns
</div><divclass="col">
One of three columns
</div><divclass="col">
One of three columns
</div></div></div>

One of three columns

One of three columns

One of three columns

Copy

<divclass="container"><divclass="row"><divclass="col align-self-start">
One of three columns
</div><divclass="col align-self-center">
One of three columns
</div><divclass="col align-self-end">
One of three columns
</div></div></div>

Horizontal alignment

One of two columns

One of two columns

One of two columns

One of two columns

One of two columns

One of two columns

One of two columns

One of two columns

One of two columns

One of two columns

Copy

<divclass="container"><divclass="row justify-content-start"><divclass="col-4">
One of two columns
</div><divclass="col-4">
One of two columns
</div></div><divclass="row justify-content-center"><divclass="col-4">
One of two columns
</div><divclass="col-4">
One of two columns
</div></div><divclass="row justify-content-end"><divclass="col-4">
One of two columns
</div><divclass="col-4">
One of two columns
</div></div><divclass="row justify-content-around"><divclass="col-4">
One of two columns
</div><divclass="col-4">
One of two columns
</div></div><divclass="row justify-content-between"><divclass="col-4">
One of two columns
</div><divclass="col-4">
One of two columns
</div></div></div>

No gutters

The gutters between columns in our predefined grid classes can be removed with .no-gutters. This removes the negative margins from .row and the horizontal padding from all immediate children columns.

Here’s the source code for creating these styles. Note that column overrides are scoped to only the first children columns and are targeted via attribute selector. While this generates a more specific selector, column padding can still be further customized with spacing utilities.

<divclass="row"><divclass="col-9">.col-9</div><divclass="col-4">.col-4<br>Since 9 + 4 = 13 &gt; 12, this 4-column-wide div gets wrapped onto a new line as one contiguous unit.</div><divclass="col-6">.col-6<br>Subsequent columns continue along the new line.</div></div>

Column resets

With the handful of grid tiers available, you’re bound to run into issues where, at certain breakpoints, your columns don’t clear quite right as one is taller than the other. To fix that, use a combination of a .clearfix and our responsive utility classes.

Nesting

To nest your content with the default grid, add a new .row and set of .col-sm-* columns within an existing .col-sm-* column. Nested rows should include a set of columns that add up to 12 or fewer (it is not required that you use all 12 available columns).

Sass mixins

When using Bootstrap’s source Sass files, you have the option of using Sass variables and mixins to create custom, semantic, and responsive page layouts. Our predefined grid classes use these same variables and mixins to provide a whole suite of ready-to-use classes for fast responsive layouts.

Variables

Variables and maps determine the number of columns, the gutter width, and the media query point at which to begin floating columns. We use these to generate the predefined grid classes documented above, as well as for the custom mixins listed below.

Mixins

Mixins are used in conjunction with the grid variables to generate semantic CSS for individual grid columns.

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// Creates a wrapper for a series of columns
@mixinmake-row($gutters:$grid-gutter-widths){display:flex;flex-wrap:wrap;@each$breakpointinmap-keys($gutters){@includemedia-breakpoint-up($breakpoint){$gutter:map-get($gutters,$breakpoint);margin-right:($gutter/-2);margin-left:($gutter/-2);}}}// Make the element grid-ready (applying everything but the width)
@mixinmake-col-ready($gutters:$grid-gutter-widths){position:relative;// Prevent columns from becoming too narrow when at smaller grid tiers by
// always setting `width: 100%;`. This works because we use `flex` values
// later on to override this initial width.
width:100%;min-height:1px;// Prevent collapsing
@each$breakpointinmap-keys($gutters){@includemedia-breakpoint-up($breakpoint){$gutter:map-get($gutters,$breakpoint);padding-right:($gutter/2);padding-left:($gutter/2);}}}@mixinmake-col($size,$columns:$grid-columns){flex:00percentage($size/$columns);width:percentage($size/$columns);// Add a `max-width` to ensure content within each column does not blow out
// the width of the column. Applies to IE10+ and Firefox. Chrome and Safari
// do not appear to require this.
max-width:percentage($size/$columns);}// Get fancy by offsetting, or changing the sort order
@mixinmake-col-offset($size,$columns:$grid-columns){margin-left:percentage($size/$columns);}@mixinmake-col-push($size,$columns:$grid-columns){left:if($size>0,percentage($size/$columns),auto);}@mixinmake-col-pull($size,$columns:$grid-columns){right:if($size>0,percentage($size/$columns),auto);}

Example usage

You can modify the variables to your own custom values, or just use the mixins with their default values. Here’s an example of using the default settings to create a two-column layout with a gap between.

Customizing the grid

Using our built-in grid Sass variables and maps, it’s possible to completely customize the predefined grid classes. Change the number of tiers, the media query dimensions, and the container widths—then recompile.

Columns and gutters

The number of grid columns and their horizontal padding (aka, gutters) can be modified via Sass variables. $grid-columns is used to generate the widths (in percent) of each individual column while $grid-gutter-widths allows breakpoint-specific widths that are divided evenly across padding-left and padding-right for the column gutters.

Grid tiers

Moving beyond the columns themselves, you may also customize the number of grid tiers. If you wanted just three grid tiers, you’d update the $grid-breakpoints and $container-max-widths to something like this:

When making any changes to the Sass variables or maps, you’ll need to save your changes and recompile. Doing so will out a brand new set of predefined grid classes for column widths, offsets, pushes, and pulls. Responsive visibility utilities will also be updated to use the custom breakpoints.